1. Field of the Invention
The present invention relates to a capsule medical apparatus which is inserted inside a subject and operates on supplied power to execute a predetermined function, and a current-carrying control method thereof.
2. Description of the Related Art
In recent years, a swallowable capsule medical apparatus has been proposed in a field of endoscope. One of the capsule medical apparatuses is a capsule endoscope which has an imaging function and a radio communication function provided inside a capsule-like casing. The capsule endoscope is swallowed by a subject (human body) from the mouth for observation (examination), moves through inside body cavities such as internal organs, e.g., a stomach and a small intestine, following peristaltic movements thereof and sequentially captures images until naturally discharged.
Image data acquired through imaging by the capsule endoscope while the capsule endoscope travels through the body cavities inside the body is sequentially transmitted outside by radio communication, and stored in a memory provided outside. When the subject carries a receiver which is provided with a radio communication function and a memory function, the subject can move freely after swallowing the capsule endoscope until discharging the same. After the capsule endoscope is discharged, a doctor or a nurse can make diagnosis by displaying images of internal organs on a screen based on the image data stored in the memory (see Japanese Patent Application Laid-Open No. 2003-210395).
In the capsule endoscope as described above, a reed switch, which operates according to an external magnetic field, is sometimes employed for supplying power to each function executing unit from a power supply. In general, a longitudinal direction of the conventional reed switch is set vertical to a direction of a longitudinal axis of the capsule endoscope, and a direction of a magnetic field and a lead extending direction of the reed switch are required to coincide with each other.
The capsule endoscope is formed rotationally-symmetrical about the direction of the longitudinal axis, and a position in the rotational direction is not particularly defined. Therefore, it is difficult to make the direction of the magnetic field and the lead extending direction of the reed switch coincide with each other. For example, in order to activate the reed switch, it is necessary to move a magnet which generates the magnetic field around the reed switch to check the orientation of the reed switch. Thus, on/off operations of the reed switch are cumbersome.